Numerical Simulation of the Wave Pattern within a Harbor due to Ship Waves

2002 ◽  
Vol 16 (4) ◽  
pp. 315-325
Author(s):  
Pablo A. Tarela ◽  
Angel N. Menéndez
Keyword(s):  
Numerical Simulation ◽  
Wave Pattern ◽  
Ship Waves

Diffraction Waves About an Advancing Wedge Model in Deep Water

1990 ◽  
Vol 34 (02) ◽  
pp. 105-122
Author(s):  
Hideaki Miyata ◽  
Makoto Kanai ◽  
Noriaki Yoshiyasu ◽  
Yohichi Furuno
Keyword(s):  
Numerical Simulation ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Wedge Angle ◽  
Wave Pattern ◽  
Regular Waves ◽  
Nonlinear Characteristics ◽  
Diffracted Waves ◽  
Nonlinear Features ◽  
Incident Waves

The diffraction of regular waves by advancing wedge models is studied both experimentally and numerically. The nonlinear features of diffracted waves are visualized by wave pattern pictures and the formation is analyzed by the grid-projection method. The experimental observation indicates that the diffracted waves have a number of nonlinear characteristics similar to shock waves due to the interaction of incident waves with the advancing obstacle in the flow-field caused by the advancing motion. Bow waves of both oblique type and normal detached type are observed at remarkably lower Froude numbers than in the case of a ship in steady advance motion. Their occurrence systematically depends on the Froude number and the wedge angle. The numerical simulation of this phenomenon by a finite-difference method shows approximate agreement with the experimental results.

Reflection and Transmission of Ship Waves by Floating Barriers

2002 ◽  
Author(s):  
Quan-Ming Miao ◽  
Allen T. Chwang
Keyword(s):  
Free Surface ◽  
Energy Density ◽  
Wave Energy ◽  
Outer Region ◽  
Wave Pattern ◽  
Transmission Performance ◽  
Reflection And Transmission ◽  
Ship Waves ◽  
Wave Energy Density

The reflection and transmission of ship waves by vertical floating barriers located on both sides of a fairway are investigated by the modified Dawson’s method in this paper. The free surface is specially treated to take into account the floating barriers. The wave pattern and the wave energy density between and outside the barriers are obtained. It is found that the reflection and transmission performance of a barrier is associated with its width and height. For a wider or higher barrier, more ship waves are reflected by it. A vertical floating barrier with a reasonable width and height can reduce ship waves in the outer region very efficiently.

Surface Gravity Waves

2017 ◽  
Author(s):  
John A. Adam
Keyword(s):  
Gravity Waves ◽  
Water Waves ◽  
Water Surface ◽  
Wave Pattern ◽  
The Body ◽  
Surface Gravity ◽  
Shallow Water Waves ◽  
Ship Waves ◽  
Surface Gravity Waves ◽  
Basic Fluid

This chapter deals with the underlying mathematics of surface gravity waves, defined as gravity waves observed on an air–sea interface of the ocean. Surface gravity waves, or surface waves, differ from internal waves, gravity waves that occur within the body of the water (such as between parts of different densities). Examples of gravity waves are wind-generated waves on the water surface, as well tsunamis and ocean tides. Wind-generated gravity waves on the free surface of the Earth's seas, oceans, ponds, and lakes have a period of between 0.3 and 30 seconds. The chapter first describes the basic fluid equations before discussing the dispersion relations, with a particular focus on deep water waves, shallow water waves, and wavepackets. It also considers ship waves and how dispersion affects the wave pattern produced by a moving object, along with long and short waves.

From Bulbous Bow to Free-Surface Shock Wave—Trends of 20 Years’ Research on Ship Waves at the Tokyo University Tank

1981 ◽  
Vol 25 (03) ◽  
pp. 147-180
Author(s):  
Takao Inui
Keyword(s):  
Shock Wave ◽  
Free Surface ◽  
Field Measurements ◽  
Wave Pattern ◽  
Ship Waves ◽  
Second Stage ◽  
Initial Stage ◽  
Man And Nature ◽  
Bulbous Bow ◽  
The Relationship

Trends of 20 years' research on ship waves at the Tokyo University Tank since 1960 are briefly sketched. Stress is focused on the importance of dialogues between man and nature. The process of these dialogues is exemplified by some typical cases, including the development of bulbous bows and the finding of free-surface shock waves. Wave-pattern pictures are shown to be indispensable for the initial stage of the di alogues, while wave contours and velocity-field measurements serve well in the second stage. The current wave analysis and wake survey may be the third. The relationship between "wavebreaking" and the "free-surface shock wave" is also discussed.

Viscosity, Wake, and Ship Waves

1970 ◽  
Vol 14 (04) ◽  
pp. 207-240
Author(s):  
Roger Brard
Keyword(s):  
Wave Pattern ◽  
Viscous Resistance ◽  
Total Resistance ◽  
Wave Analysis ◽  
Ship Waves ◽  
Wake Survey

In this paper a theory of the effect of viscosity on ship waves is presented. It is shown that the wake affects the singularities kinematically equivalent to the hull and generates waves which modify the resulting wave pattern. The theory may explain why the estimate of the viscous resistance obtained by means of a wake survey and the estimate of the wavemaking resistance obtained by means of a wave analysis do not add up, in general, to the total resistance measured by using a dynamometer. The discrepancy seems to be due essentially to the existence of a wavemaking viscous resistance.

Zero wave resistance for ships moving in shallow channels at supercritical speeds

1997 ◽  
Vol 335 ◽  
pp. 305-321 ◽  
Author(s):  
XUE-NONG CHEN ◽  
SOM DEO SHARMA
Keyword(s):  
Shallow Water ◽  
Water Channel ◽  
Wave Theory ◽  
Wave Pattern ◽  
Wave Resistance ◽  
Kp Equation ◽  
Nonlinear Case ◽  
Hull Form ◽  
Ship Waves ◽  
Shallow Channel

This paper deals with the wave pattern and wave resistance of a slender ship moving steadily at supercritical speed in a shallow water channel. Using, successively, linear and nonlinear shallow-water wave theory it is demonstrated that, if the hull form is adapted to speed and channel geometry according to certain rules, the ship waves can be made to form a localized pattern around the ship that moves at the same speed as the ship and at the same time the associated wave resistance can be made to vanish. In the nonlinear case, the zero-wave-resistance ship hull is derived from a KP equation solution of the oblique interaction of two identical solitons. This astonishing phenomenon may be called shallow-channel superconductivity.

Nonlinear Ship Waves at Low Froude Number

1989 ◽  
Vol 33 (03) ◽  
pp. 176-193
Author(s):  
A. J. Hermans ◽  
F. J. Brandsma
Keyword(s):  
Free Surface ◽  
Froude Number ◽  
Continuous Dependence ◽  
Wave Pattern ◽  
Ray Method ◽  
Ship Waves ◽  
Asymptotic Evaluation ◽  
Low Froude Number ◽  
Field Wave

The wave pattern of a thick ship-like object with finite bow and stern angles 0 <β<π/2 is studied. The completely blunt form p = π/2 is excluded. It turns out that the wave pattern is strongly influenced by the nonlinear terms at the free surface. The wave pattern is determined by means of the ray method. The rays are generated mainly at the bow and the stern. A crucial step is the determination of the so-called excitation coefficients. They are constructed by means of an asymptotic evaluation of a distribution of "local"sources at the free surface. It is shown that for small angles β<< 1 the excitation coefficients are the same as the ones obtained by means of an asymptotic expansion for small values of the Froude number of the results of Michell's thin-ship theory. For increasing values of β, the excitation coefficients change asymptotically. The theory herein shows a continuous dependence, nevertheless. Similar changes are observed in the far-field wave pattern.

The Comprehensive Analysis to the High Precipitation Supercell Affecting Guangxi

2011 ◽  
Vol 137 ◽  
pp. 362-368
Author(s):  
Xiang Hong Li ◽  
Li Hong Yao ◽  
Zhen Ming Lin
Keyword(s):  
Numerical Simulation ◽  
Radial Velocity ◽  
Cross Section ◽  
Central Region ◽  
Simulation Analysis ◽  
Elevation Angle ◽  
Wave Pattern ◽  
Comprehensive Analysis ◽  
Radar Reflectivity ◽  
High Precipitation

From 31 May to 1 June 2010, serious super high precipitation multi-cells caused convectional rainstorm in central region of Guangxi. The heaviest hour rainfall was 92mm, the heaviest rainfall for 48 hours was 503.9mm. The storms developed in the southwest warm moist wind and moved rightly. The radar reflectivity displayed several bow echoes moving from west to east along the 850hPa shear line. A line echo wave pattern developed. At 2.4°elevation angle, the maximum radar reflectivity of supercell reached 69dBz. The cross section of reflectivity showed that the 40dBz reflectivity core reached 9km in height, indicating a deep updraft. The radial velocity imagery showed with the mesocyclone features such as inverse wind area, the positive and negative velocity pairs. The VAD profile showed the deep warm-wet layer before the storm occurred. The 12m/s southwest wind reached 8km in depth. About 2 hours before the rainstorm, the VAD profile showed double dry region. When the double dry region appeared half hour later, the first rainstorm occurred. The numerical simulation analysis results indicated that the high precipitation multi-cell storms was produced and moved along the vortex path.

scholarly journals NUMERICAL SIMULATION OF SHIP WAVES IN SHALLOW WATER

2000 ◽  
Vol 16 ◽  
pp. 375-380
Author(s):  
Katsutoshi TANIMOTO ◽  
Hidetaka KOBAYASHI ◽  
Katsuhiko KURATA ◽  
Hiroshi KONNO
Keyword(s):  
Numerical Simulation ◽  
Shallow Water ◽  
Ship Waves

Reflection and Transmission of Ship Waves by Floating Barriers

2003 ◽  
Vol 125 (1) ◽  
pp. 54-58
Author(s):  
Quan-Ming Miao ◽  
Allen T. Chwang
Keyword(s):  
Free Surface ◽  
Energy Density ◽  
Wave Energy ◽  
Outer Region ◽  
Wave Pattern ◽  
Transmission Performance ◽  
Reflection And Transmission ◽  
Ship Waves ◽  
Wave Energy Density

The reflection and transmission of ship waves by vertical floating barriers located on both sides of a fairway are investigated by the modified Dawson’s method in this paper. The free surface is specially treated to take into account the floating barriers. The wave pattern and the wave energy density between and outside the barriers are obtained. It is found that the reflection and transmission performance of a barrier is associated with its width and height. For a wider or higher barrier, more ship waves are reflected by it. A vertical floating barrier with a reasonable width and height can reduce ship waves in the outer region very efficiently.

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